Fixed error in FixedSizeListArray::new_null

src/array/fixed_size_list/mod.rs

@@ -84,6 +84,11 @@ impl FixedSizeListArray {
         Self::try_new(data_type, values, validity).unwrap()
     }
 
+    /// Returns the size (number of elements per slot) of this [`FixedSizeListArray`].
+    pub const fn size(&self) -> usize {
+        self.size
+    }
+
     /// Alias for `new`
     pub fn from_data(
         data_type: DataType,
@@ -101,10 +106,9 @@ impl FixedSizeListArray {
 
     /// Returns a new null [`FixedSizeListArray`].
     pub fn new_null(data_type: DataType, length: usize) -> Self {
-        let values = new_null_array(
-            Self::get_child_and_size(&data_type).0.data_type().clone(),
-            length,
-        );
+        let (field, size) = Self::get_child_and_size(&data_type);
+
+        let values = new_null_array(field.data_type().clone(), length * size);
         Self::new(data_type, values, Some(Bitmap::new_zeroed(length)))
     }
 

tests/it/array/fixed_size_list/mod.rs

@@ -1 +1,104 @@
 mod mutable;
+
+use arrow2::{
+    array::*,
+    bitmap::Bitmap,
+    datatypes::{DataType, Field},
+};
+
+fn data() -> FixedSizeListArray {
+    let values = Int32Array::from_slice([10, 20, 0, 0]);
+
+    FixedSizeListArray::try_new(
+        DataType::FixedSizeList(
+            Box::new(Field::new("a", values.data_type().clone(), true)),
+            2,
+        ),
+        values.boxed(),
+        Some([true, false].into()),
+    )
+    .unwrap()
+}
+
+#[test]
+fn basics() {
+    let array = data();
+    assert_eq!(array.size(), 2);
+    assert_eq!(array.len(), 2);
+    assert_eq!(array.validity(), Some(&Bitmap::from([true, false])));
+
+    assert_eq!(array.value(0).as_ref(), Int32Array::from_slice([10, 20]));
+    assert_eq!(array.value(1).as_ref(), Int32Array::from_slice([0, 0]));
+
+    let array = array.slice(1, 1);
+
+    assert_eq!(array.value(0).as_ref(), Int32Array::from_slice([0, 0]));
+}
+
+#[test]
+fn with_validity() {
+    let array = data();
+
+    let a = array.with_validity(None);
+    assert!(a.validity().is_none());
+}
+
+#[test]
+fn debug() {
+    let array = data();
+
+    assert_eq!(format!("{:?}", array), "FixedSizeListArray[[10, 20], None]");
+}
+
+#[test]
+fn empty() {
+    let array = FixedSizeListArray::new_empty(DataType::FixedSizeList(
+        Box::new(Field::new("a", DataType::Int32, true)),
+        2,
+    ));
+    assert_eq!(array.values().len(), 0);
+    assert_eq!(array.validity(), None);
+}
+
+#[test]
+fn null() {
+    let array = FixedSizeListArray::new_null(
+        DataType::FixedSizeList(Box::new(Field::new("a", DataType::Int32, true)), 2),
+        2,
+    );
+    assert_eq!(array.values().len(), 4);
+    assert_eq!(array.validity().cloned(), Some([false, false].into()));
+}
+
+#[test]
+fn wrong_size() {
+    let values = Int32Array::from_slice([10, 20, 0]);
+    assert!(FixedSizeListArray::try_new(
+        DataType::FixedSizeList(Box::new(Field::new("a", DataType::Int32, true)), 2),
+        values.boxed(),
+        None
+    )
+    .is_err());
+}
+
+#[test]
+fn wrong_len() {
+    let values = Int32Array::from_slice([10, 20, 0]);
+    assert!(FixedSizeListArray::try_new(
+        DataType::FixedSizeList(Box::new(Field::new("a", DataType::Int32, true)), 2),
+        values.boxed(),
+        Some([true, false, false].into()), // it should be 2
+    )
+    .is_err());
+}
+
+#[test]
+fn wrong_data_type() {
+    let values = Int32Array::from_slice([10, 20, 0]);
+    assert!(FixedSizeListArray::try_new(
+        DataType::Binary,
+        values.boxed(),
+        Some([true, false, false].into()), // it should be 2
+    )
+    .is_err());
+}